Biomedical subjects

Joel E Michalek

Publications and source records attributed to Joel E Michalek.

18 recordsLinked to original sources

PubMed2006

MCP-1 deficiency causes altered inflammation with impaired skeletal muscle regeneration.

We examined the role of MCP-1, a potent chemotactic and activating factor for macrophages, in perfusion, inflammation, and skeletal muscle regeneration post-ischemic injury. MCP-1-/- or C57Bl/6J control mice [wild-type (WT)] underwent femoral artery excision (FAE). Muscles were collected for histology, assessment of tissue chemokines, and activity measurements of lactate dehydrogenase (LDH) and myeloperoxidase. In MCP-1-/- mice, restoration of perfusion was delayed, and LDH and fiber size, indicators of muscle regeneration, were decreased. Altered inflammation was observed with increased neutrophil accumulation in MCP-1-/- versus WT mice at Days 1 and 3 (P< or =0.003), whereas fewer macrophages were present in MCP-1-/- mice at Day 3. As necrotic tissue was removed in WT mice, macrophages decreased (Day 7). In contrast, macrophage accumulation in MCP-1-/- was increased in association with residual necrotic tissue and impaired muscle regeneration. Consistent with altered inflammation, neutrophil chemotactic factors (keratinocyte-derived chemokine and macrophage inflammatory protein-2) were increased at Day 1 post-FAE. The macrophage chemotactic factor MCP-5 was increased significantly in WT mice at Day 3 compared with MCP-1-/- mice. However, at post-FAE Day 7, MCP-5 was significantly elevated in MCP-1-/- mice versus WT mice. Addition of exogenous MCP-1 did not induce proliferation in murine myoblasts (C2C12 cells) in vitro. MCP-1 is essential for reperfusion and the successful completion of normal skeletal muscle regeneration after ischemic tissue injury. Impaired muscle regeneration in MCP-1-/- mice suggests an important role for macrophages and MCP-1 in tissue reparative processes.

Animals↗

PubMed2006

Covariation of psychological attributes and incident coronary heart disease in U.S. Air Force veterans of the Vietnam war.

OBJECTIVE: The purpose of the present investigation was to examine the prospective associations of hostility, anger, depression, and anxiety, alone and in combination, to incident coronary heart disease (CHD). METHODS: Subjects were 2105 men who participated in the Air Force Health Study, a 20-year study designed to evaluate the effects of herbicide exposure on various health outcomes in Air Force veterans of Operation Ranch Hand. Psychological attributes were assessed in 1985 using scales constructed from the Minnesota Multiphasic Personality Inventory. Participants were followed for an average of 15 years for evidence of ischemic heart disease (International Classification of Diseases codes 410-414, 428.4, or 36). The relation between psychological attributes and CHD was examined with Cox proportional hazard models. RESULTS: Adjusting for CHD risk factors, depression, anxiety, hostility, and trait anger were significant predictors of incident CHD. In addition, a factor analytically derived psychological risk factor composite score was the strongest predictor of CHD. CONCLUSIONS: These results suggest that the covariation of hostility, anger, depression, and anxiety accounts for the increased risk of CHD associated with each individual factor. The results of this study challenge the conventional approach of examining these psychological attributes in isolation.

Adult↗

PubMed2006

Fat accumulation with altered inflammation and regeneration in skeletal muscle of CCR2-/- mice following ischemic injury.

Chemokines recruit inflammatory cells to sites of injury, but the role of the CC chemokine receptor 2 (CCR2) during regenerative processes following ischemia is poorly understood. We studied injury, inflammation, perfusion, capillary formation, monocyte chemotactic protein-1 (MCP-1) levels, muscle regeneration, fat accumulation, and transcription factor activation in hindlimb muscles of CCR2-/- and wild-type (WT) mice following femoral artery excision (FAE). In both groups, muscle injury and restoration of vascular perfusion were similar. Nevertheless, edema and neutrophil accumulation were significantly elevated in CCR2-/- compared with WT mice at day 1 post-FAE and fewer macrophages were present at day 3. MCP-1 levels in post-ischemic calf muscle of CCR2-/- animals were significantly elevated over baseline through 14 days post-FAE and were higher than WT mice at days 1, 7, and 14. In addition, CCR2-/- mice exhibited impaired muscle regeneration, decreased muscle fiber size, and increased intermuscular adipocytes with similar capillaries/mm(2) postinjury. Finally, the transcription factors, MyoD and signal transducers of and activators of transcription-3 (STAT3), were significantly increased above baseline but did not differ significantly between groups at any time point post-FAE. These findings suggest that increases in MCP-1, and possibly, MyoD and STAT3, may modulate molecular signaling in CCR2-/- mice during inflammatory and regenerative events. Furthermore, alterations in neutrophil and macrophage recruitment in CCR2-/- mice may critically alter the normal progression of downstream regenerative events in injured skeletal muscle and may direct myogenic precursor cells in the regenerating milieu toward an adipogenic phenotype.

Adipocytes↗

PubMed2006

Prostate cancer in US Air Force veterans of the Vietnam war.

US Air Force veterans of Operation Ranch Hand sprayed herbicides contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in Vietnam from 1962 to 1971. Comparisons served in Southeast Asia (SEA) during the same time period but did not spray herbicides. Here we investigate a potential association between exposure to TCDD and prostate cancer. Data were available for 2516 veterans (1019 Ranch Hand and 1497 Comparison) who participated in at least one of six physical examinations starting in 1982 and had a measurement of serum TCDD. We assigned Ranch Hands to two exposure categories: Lower and Higher, based on their median 20-year cumulative TCDD level. In total, 81 Comparison and 59 Ranch Hand prostate cancers were identified between 1 January 1982 and 31 December 2003. We found no overall increase in the risk of prostate cancer in Ranch Hand veterans versus the Comparisons. There was a positive association in Ranch Hand veterans in the Higher TCDD category who served in SEA before 1969 (RR=2.27, 95% CI 1.11-4.66) when more contaminated herbicides were used, but the number of cases was small (n=15). A within-group comparison found that in Comparison veterans, time served in SEA was associated with an increased risk of prostate cancer (RR=2.18, 95% CI 1.27-3.76, >789 days versus < or =789 days). No increase in the risk of prostate cancer was observed within the Ranch Hand group in association with TCDD or time served in SEA. These analyses suggest that a longer service in SEA and exposures other than TCDD may have increased the risk of prostate cancer in Comparison veterans.

2,4,5-Trichlorophenoxyacetic Acid↗

PubMed2006

Evaluating efficacy of a chitosan product using a double-blinded, placebo-controlled protocol.

OBJECTIVE: To examine the safety and efficacy of a chitosan dietary supplement on body composition under free-living conditions. DESIGN: In a randomized, double-blinded, placebo-controlled dietary intervention protocol, subjects were assigned to a treatment group (TRT), a placebo group (PLA) and a control group (CTL). SUBJECTS: A total of 150 overweight adults enrolled; 134 (89.3%) completed the study; 111 (82.8%) were women who were similarly distributed in the three groups. INTERVENTION: The TRT group took six 500 mg chitosan capsules per day and both TRT and PLA groups wore pedometers during their waking hours and recorded daily step totals. The CTL group followed weight loss programs of their choice, and took the same baseline and ending tests. MEASURES OF OUTCOME: Outcome measures were Dual Energy X-ray Absorptiometry tests, fasting blood chemistries, and self-reported daily activity levels and caloric intakes. RESULTS: Compared to CTL, the TRT group lost more weight (-2.8 lbs vs. +0.8 lbs, p < 0.001) and fat mass (-2.6 lbs vs. +0.1 lbs, p = 0.006). Compared to PLA, the TRT group lost more weight (-2.8 lbs. vs. -0.6 lbs, p = 0.03), % fat (-0.8% vs. +0.4%, p = 0.003), fat mass (-2.6 lbs vs. +0.6 lbs, p = 0.001) and had a greater body composition improvement index (BCI) (+2.4 lbs vs. -1.9 lbs, p = 0.002). CONCLUSIONS: These data provide evidence for the efficacy of a chitosan compound to facilitate the depletion of excess body fat under free-living conditions with minimal loss of fat-free or lean body mass.

Absorptiometry, Photon↗

PubMed2006

Serum dioxin, testosterone, and subsequent risk of benign prostatic hyperplasia: a prospective cohort study of Air Force veterans.

BACKGROUND: Operation Ranch Hand veterans were involved in spraying herbicides, including Agent Orange, during the Vietnam War in 1962-1971; Agent Orange was contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). It has been hypothesized that dioxins may be partially responsible for an increase of male reproductive tract disorders such as testicular cancer, cryptorchidism, and hypospadias. OBJECTIVES: In this study, our objective was to assess the effect of serum TCDD concentration on the risk of development of benign prostatic hyperplasia (BPH) and on serum testosterone levels. METHODS: This study was a longitudinal, prospective cohort study made up of U.S. Air Force veterans involved in Operation Ranch Hand. Other Air Force veterans who did not spray herbicides were included as comparisons. BPH was determined by medical record review and by medical examinations conducted during the study. Data were available for 971 Ranch Hand and 1,266 comparison veterans. We investigated the relationship between BPH and serum TCDD level using the Cox proportional hazards models adjusted for testosterone levels, body mass index (BMI), and the percentage change in BMI per year. RESULTS: In univariate and multivariate analyses, the risk of BPH decreased with increasing serum TCDD in the comparison group. The multivariate risk ratio for BPH in the comparison group was 0.84 (95% confidence interval, 0.73-0.98). Excluding men with prostate cancer, inflammatory or other prostatic diseases did not substantially alter the association. Serum testosterone levels were inversely associated with serum TCDD levels in both Ranch Hand and comparison groups. CONCLUSIONS: TCDD exposure at general population levels is associated with a decreasing risk of BPH with higher exposure levels. TCDD exposure is also negatively associated with serum testosterone levels.

Dioxins↗

PubMed2005

A randomized trial of a strategy for increasing high-density lipoprotein cholesterol levels: effects on progression of coronary heart disease and clinical events.

BACKGROUND: The high-density lipoprotein (HDL) cholesterol level is a strong predictor of cardiovascular events in epidemiologic studies. Until recently, it has been less extensively studied as a therapeutic target. OBJECTIVE: To assess the angiographic and clinical effects of a pharmacologic strategy to increase HDL cholesterol levels. DESIGN: Randomized, double-blind, placebo-controlled trial conducted from 1993 to 1996. SETTING: Outpatient specialty clinic of a large U.S. military medical center. PARTICIPANTS: 143 military retirees younger than 76 years of age with low HDL cholesterol levels and angiographically evident coronary disease. INTERVENTION: Gemfibrozil, niacin, and cholestyramine or corresponding placebos, with aggressive dietary and lifestyle intervention at baseline. MEASUREMENTS: Change from baseline to 30 months and a composite measure of clinical events that included hospitalization for angina, myocardial infarction, transient ischemic attack and stroke, death, and cardiovascular procedures. RESULTS: At baseline, mean (+/-SD) lipid values were as follows: total cholesterol, 5.1 +/- 0.8 mmol/L (196 +/- 31 mg/dL); low-density lipoprotein (LDL) cholesterol, 3.3 +/- 0.7 mmol/L (128 +/- 27 mg/dL); and HDL cholesterol, 0.9 +/- 0.2 mmol/L (34 +/- 6 mg/dL). Compared with placebo, the pharmacologically treated group experienced a 20% (95% CI, 14.8% to 24.3%) decrease in total cholesterol level, a 36% (CI, 28.4% to 43.5%) increase in HDL cholesterol level, a 26% (CI, 19.1% to 33.7%) decrease in LDL cholesterol level, and a 50% (CI, 40.5% to 59.2%) reduction in triglyceride levels. Focal coronary stenosis increased by 1.4% in the placebo group but decreased by 0.8% in the drug group (difference, -2.2 percentage points [CI, -4.2 to -0.1 percentage points]). A composite cardiovascular event end point was reached in 26% of patients in the placebo group and 13% of those in the drug group (difference, 13.7 percentage points [CI, 0.9 to 26.5 percentage points]). Side effects, particularly flushing and gastrointestinal intolerance, were more common in the drug group but rarely led to withdrawal from the study. LIMITATIONS: The study was small and used a composite clinical outcome. Whether improvements in angiographic findings were due to reductions in LDL cholesterol or increases in HDL cholesterol was not established. Flushing may have led to inadvertent unblinding in patients who were randomly assigned to active study drugs. CONCLUSIONS: A combination regimen aimed at increasing HDL cholesterol levels improves cholesterol profiles, helps prevent angiographic progression of coronary stenosis, and may prevent cardiovascular events in some people who exercise regularly and eat low-fat diets.

Aged↗

PubMed2005

Amalgam exposure and neurological function.

Concerns regarding the safety of silver-mercury amalgam fillings continue to be raised in the absence of any direct evidence of harm. The widespread population exposure to amalgam mandated that a thorough investigation be conducted of its potential effects on the nervous system. The National Institute of Dental and Craniofacial Research and U.S. Air Force investigators collaborated in the ongoing Air Force Health Study (AFHS) of Vietnam era veterans. The primary study question involved adverse health effects associated with exposure to herbicides or dioxin. An assessment of exposure to dental amalgam fillings was added to the 1997-1998 health examination to investigate possible associations between amalgam exposure and neurological abnormalities. Our study population consisted of 1663 dentate AFHS participants, comprised of 986 AFHS controls and 677 Ranch Hand veterans who were exposed to dioxin in Vietnam. Two hundred and fifty-two of the participants had confirmed diabetes mellitus. Study outcomes included clinical neurological signs, vibrotactile thresholds, and summary variables for different levels of peripheral neuropathy. A limitation of our study is that our database did not include more sensitive continuous measures such as nerve conduction studies. No significant associations were found between amalgam exposure and clinical neurological signs of abnormal tremor, coordination, station or gait, strength, sensation, or muscle stretch reflexes or for any level of peripheral neuropathy among our study participants. A statistically significant association was detected between amalgam exposure and the continuous vibrotactile sensation response for the combined non-diabetic participants and separately for non-diabetic AFHS controls. No significant association in this measure was detectable for non-diabetic Ranch Hand veterans or among the combined diabetic participants. The association is a sub-clinical finding that was not associated with symptoms, clinically evident signs of neuropathy, or any functional impairment. Overall, we found no association between amalgam exposure and neurological signs or clinically evident peripheral neuropathy. Our findings do not support the hypothesis that exposure to amalgam produces adverse, clinically evident neurological effects.

Dental Amalgam↗

PubMed2005

Did TCDD exposure or service in Southeast Asia increase the risk of cancer in air force Vietnam veterans who did not spray agent orange?

OBJECTIVE: We sought to examine cancer incidence in 1482 Air Force veterans who served in Southeast Asia (SEA) and who were not occupationally exposed to herbicides. METHODS: Cancer incidence between 1982 and 2003 was determined by record review and Cox proportional hazards models were used to estimate risk ratios across serum 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and years served in SEA categories. RESULTS: All sites cancer risk increased with TCDD (relative risk = 1.6, 95% confidence interval = 1.2-2.2). The risk of prostate cancer increased with years of SEA service but not with TCDD. TCDD and years of SEA service interacted with all sites cancer; the risk was greatest in those with the highest TCDD levels and the longest time served in SEA. CONCLUSIONS: These results suggest nonoccupational exposures to TCDD or other factors while in SEA may contribute to cancer risk in these veterans.

Adult↗

PubMed2005

Comparison of the use of a physiologically based pharmacokinetic model and a classical pharmacokinetic model for dioxin exposure assessments.

In epidemiologic studies, exposure assessments of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) assume a fixed elimination rate. Recent data suggest a dose-dependent elimination rate for TCDD. A physiologically based pharmacokinetic (PBPK) model, which uses a body-burden-dependent elimination rate, was developed previously in rodents to describe the pharmacokinetics of TCDD and has been extrapolated to human exposure for this study. Optimizations were performed using data from a random selection of veterans from the Ranch Hand cohort and data from a human volunteer who was exposed to TCDD. Assessment of this PBPK model used additional data from the Ranch Hand cohort and a clinical report of two women exposed to TCDD. This PBPK model suggests that previous exposure assessments may have significantly underestimated peak blood concentrations, resulting in potential exposure misclassifications. Application of a PBPK model that incorporates an inducible elimination of TCDD may improve the exposure assessments in epidemiologic studies of TCDD.

Body Burden↗

PubMed2005

Postservice mortality of Air Force veterans occupationally exposed to herbicides during the Vietnam War: 20-year follow-up results.

Since 1982, the Air Force Health Study has continued to assess the mortality for veterans of Operation Ranch Hand, the unit responsible for aerially spraying herbicides in Vietnam. The mortality for 1,262 Ranch Hand veterans to December 31, 1999 was contrasted with that for 19,078 comparison veterans. The relative risk (RR) for all-cause death was borderline significantly increased (RR, 1.15; 95% confidence interval, 1.0-1.3; p = 0.06). The risk of death caused by cancer was not increased (RR = 1.0), but the risk of death caused by circulatory system diseases was significantly increased among enlisted ground crew workers (RR = 1.7; 95% confidence interval, 1.2-2.4; p = 0.001). Results for Ranch Hand all-cause death differed from previous reports, with the RR now exceeding 1.0. The risk of death attributable to circulatory system diseases continues to be increased, especially for enlisted ground crew, a subgroup with relatively high skin exposure to herbicides.

Aerospace Medicine↗

PubMed2004

Cancer in US Air Force veterans of the Vietnam War.

Cancer incidence and mortality were summarized in Air Force veterans of the Vietnam War. The index subjects were Operation Ranch Hand veterans who sprayed 2,3,7,8 tetrachlorodibenzo-p-dioxin (dioxin)-contaminated herbicides in Vietnam. Comparisons served in Southeast Asia during the same period but did not spray herbicides. We assessed cancer incidence and mortality using national rates and contrasted cancer risk in each of three Ranch Hand dioxin exposure categories relative to comparisons. The incidence of melanoma and prostate cancer was increased among white Ranch Hand veterans relative to national rates. Among veterans who spent at most 2 years in Southeast Asia, the risk of cancer at any site, of prostate cancer and of melanoma was increased in the highest dioxin exposure category. These results appear consistent with an association between cancer and dioxin exposure.

Adult↗

PubMed2004

Insulin sensitivity following agent orange exposure in Vietnam veterans with high blood levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin.

Our objective was to determine whether insulin sensitivity was related to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in Vietnam veterans exposed to Agent Orange. Air Force veterans of Operation Ranch Hand, the unit responsible for spraying Agent Orange and other herbicides in Vietnam from 1962 to 1971, and comparison veterans who did not spray herbicides were included. We measured insulin sensitivity (S(I)) using a frequently sampled iv glucose tolerance test in a matched study of 29 matched pairs of veterans and a quantitative insulin sensitivity check index (QUICKI) based on fasting glucose and insulin in 71 matched pairs. No group differences were found with regard to the mean values of S(I), QUICKI, TNFalpha, adiponectin, and two measures of insulin secretion. However, S(I) and QUICKI decreased significantly with regard to TCDD (P = 0.01 and 0.02). A corresponding pattern (although not significant) was found for blood levels of TNFalpha and adiponectin. These data suggest that high blood TCDD levels may promote an insulin-resistant state, but the magnitude of this effect appeared to be small, such that an 18-fold increase in blood TCDD due to increased exposure resulted in only a 10% change in S(I) in the 29 matched pairs.

2,4,5-Trichlorophenoxyacetic Acid↗

PubMed2003

Diabetes mellitus and 2,3,7,8-tetrachlorodibenzo-p-dioxin elimination in veterans of Operation Ranch Hand.

Using multivariate statistical models, no significant relationship was found between the rate of 2,3,7,8-tetrachlorodibenzo-p-dioxin ( TCDD) elimination and the occurrence or time to onset of diabetes in 343 veterans of Operation Ranch Hand, the unit responsible for the aerial spraying of Agent Orange and other TCDD-contaminated herbicides during the Vietnam War. Without adjustment for age, body mass index, family history of diabetes, and smoking history, the time to onset of diabetes decreased and the risk of diabetes increased with a diminished elimination rate. However, after adjustment, diabetes time to onset and occurrence were not significantly associated with TCDD elimination. Analyses of covariance found no significant difference between the average elimination rates of diabetic and nondiabetic veterans, without or with adjustment for risk factors. To our knowledge, this is the only study to date to examine TCDD elimination and diabetes.

Adipose Tissue↗

PubMed2003

Serum 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) levels and thyroid function in Air Force veterans of the Vietnam War.

PURPOSE: We assessed potential health effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) concentration in serum on thyroid function in US Air Force veterans involved in Operation Ranch Hand, the unit responsible for the aerial spraying of herbicides, including TCDD-contaminated Agent Orange, during the Vietnam War from 1962 to 1971. Other Air Force veterans who were not involved with spraying herbicides were included as Comparisons. METHODS: We analyzed thyroxine (total T4), thyroid stimulating hormone (TSH), triiodothyronin percent uptake (T3% uptake), the free thyroxine index (FTI), and thyroid diseases against serum TCDD levels. Data was available for 1,009 Ranch Hand and 1,429 Comparison veterans compliant to any of five examinations in 1982, 1985, 1987, 1992, and 1997. Each veteran was assigned to one of four exposure categories based on serum TCDD levels, named Comparison, Ranch Hand Background, Ranch Hand Low Elevated, and Ranch Hand High Elevated. RESULTS: Cross-sectional analyses found statistically significantly increased TSH means at the 1985 and 1987 examinations in the High category and a significant increasing trend across the three Ranch Hand TCDD categories in 1982, 1985, 1987 and 1992. A repeated-measures analysis found significantly increased TSH means in the High TCDD category. We found no significant relation between the occurrence of thyroid disease and TCDD category. CONCLUSIONS: These findings suggest that TCDD affects thyroid hormone metabolism and function in Ranch Hand veterans. Further follow-up will be necessary to understand the relation, if any, between thyroid disease and TCDD levels.

Adult↗

PubMed2003

Serum dioxin and psychological functioning in U.S. Air Force veterans of the Vietnam War.

Using the Minnesota Multiphasic Personality Inventory and the Millon Clinical Multiaxial Inventory, we assessed the psychological functioning of U.S. Air Force veterans exposed to Agent Orange and its contaminant, 2,3,7,8-tetrachlodibenzo-p-dioxin (dioxin), during the Vietnam War. Index subjects were veterans of Operation Ranch Hand (N = 1,109). Comparisons (N = 1,493) were U.S. Air Force veterans not involved with spraying herbicides. We found few consistent psychological abnormalities associated with serum dioxin levels. Ranch Hand veterans with higher dioxin levels showed some difficulties in anxiety, somatization, depression, and a denial of psychological factors. However, those with background levels also showed indications of emotional distress, primarily in emotional numbing and lability; a guarded, suspicious, and withdrawn style of relating to others; and unusual thoughts or behaviors.

2,4,5-Trichlorophenoxyacetic Acid↗

PubMed2000

Changes in the concentrations of amino acids in the cerebrospinal fluid that correlate with pain in patients with fibromyalgia: implications for nitric oxide pathways.

Substance P (SP), a putative nociceptive transmitter, is increased in the CSF of patients with fibromyalgia syndrome (FMS). Because excitatory amino acids (EAAs) also appear to transmit pain, we hypothesized that CSF EAAs may be similarly involved in this syndrome. We found that the mean concentrations of most amino acids in the CSF did not differ amongst groups of subjects with primary FMS (PFMS), fibromyalgia associated with other conditions (SFMS), other painful conditions not exhibiting fibromyalgia (OTHER) or age-matched, healthy normal controls (HNC). However, in SFMS patients, individual measures of pain intensity, determined using an examination-based measure of pain intensity, the tender point index (TPI), covaried with their respective concentrations of glutamine and asparagine, metabolites of glutamate and aspartate, respectively. This suggests that re-uptake and biotransformation mask pain-related increases in EAAs. Individual concentrations of glycine and taurine also correlated with their respective TPI values in patients with PFMS. While taurine is affected by a variety of excitatory manipulations, glycine is an inhibitory transmitter as well as a positive modulator of the N-methyl-D-asparate (NMDA) receptor. In both PFMS and SFMS patients, TPI covaried with arginine, the precursor to nitric oxide (NO), whose concentrations, in turn, correlated with those of citrulline, a byproduct of NO synthesis. These events predict involvement of NO, a potent signaling molecule thought to be involved in pain processing. Together these metabolic changes that covary with the intensity of pain in patients with FMS may reflect increased EAA release and a positive modulation of NMDA receptors by glycine, perhaps resulting in enhanced synthesis of NO.

Adult↗

PubMedDate not supplied

Pharmacokinetics of 2,3,7,8-tetrachlorodibenzo-p-dioxin in Seveso adults and veterans of operation Ranch Hand.

A combined analysis of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) elimination in Seveso adults and Ranch Hand veterans found a period of fast elimination within the first 0.27 years after exposure in Seveso, followed by a period of slower elimination between 3 and 16.35 years from exposure. The mean TCDD elimination rate within the first 0.27 years after exposure among six adult males in the Seveso cohort was 2.0646 year(-1) (half-life=0.34 years). The mean rate from 3 to 16.35 years was 0.1011 year(-1) (half-life=6.9 years). The mean Ranch Hand elimination rate, 00924 year(-1) (half-life=6.9 years), measured between 9 and 33 years after exposure, was significantly less than the Seveso mean in the first 0.27 years after exposure, but not significantly different from the Seveso mean between 3 and 16.35 years after exposure. The fast elimination within the first 0.27 years followed by a slower rate after 3 years is consistent with the expected pattern in a two-compartment open model, with a distribution phase of rapid elimination followed by a slower elimination phase.

Accidents, Occupational↗